Logically, the MVD can be divided into east and west halves, and each half is read out to its north and south ends. Thus here are 4 motherboards with connections to the outside world.

In each quarter, there are 42 MCM temperature sensors, and 35 LDO voltages to be read out. In addition, the temperature at 3 locations on the motherboard is monitored, for a total of 80 voltages per quarter. There is not enough space to feed 80 signals out, so they are converted by scanning ADC's on the motherboard, multiplexed together and fed out over a serial link, one per motherboard. The serial lines go to the MVD 'Black Box', which is a 6U VME crate, with a MVME 162 controller running VxWorks, so that it can be part of the EPICS system, as well as allow easy access to, and control of the modules in the crate.

The serial lines are handled by digital I/O module 'Industry Packs' (xxx), 4 of which fit on a carrier board (xxx). EPICS drivers exist for these modules.

Each MCM also has 2 analog spy lines, one connected to the preamp output and one to the AMU output, for a total of 42x2 per quarter. These signals are multiplexed on the motherboard, so that only 2 analog lines per quarter are fed out. In the 'serial control and spy modules' in the ancillary crate the analog signals are forwarded to the control room via opto-isolated line driver chips, on 4 twisted pairs. In the control room we can look at the analog signals with a scope. A separate page shows this scheme in some detail.

There are about 20 more signals generated by temperature, flow and humidity probes located on or near the cooling units. We have fabricated a 64-channel multiplexing ADC board, housed on a 6U single-wide VME board to read these out. The circuitry is essentially copied from the motherboards.

Temperature sensor details: The temperature sensors on board the MVD are thermistors from Analog Devices Inc. We will use the AD590, together with the TMP12 and the ADT14 chips. The thermistor takes 5V in, and produce a current proportional to the temperature. The current is sent across a 2K resistor, and the voltage across this resistor is what is read out. For more details look here.
The external temperature, flow, humidity sensors come from Omega. Details here.

There will be (approximately) 8 pin-diode radiation monitors, 4 on each pole face. These will be in place before the MVD is installed to characterize the radiation environment, and will remain in place after MVD installation. Each unit has its own amp and discriminator.

The Black Box will also contain the interface (CC-121) to the standard Phenix HV system (LeCroy 1458). A patch panel is needed to convert the HV supply cables/connectors to the cables/connectors which go up to the MVD. This patch panel is a passive module inthe Black Box.

In addition the box provides low voltage to the crate which houses the MVD interface boards (DCM, timing, control, trigger inerface modules), and power to the external sensors. These low-voltage are likely to be 5 double-wide 6U modules. There is no room in the crate for all this, so the LV modules will be housed in a separate crate.